It is well known that trailers have a tendency to weave or sway, particularly when the towing vehicle is travelling at high speeds along a straight path, and that this problem is aggravated when a number of vehicles are interconnected in a train of vehicles. Various different vehicle couplings have heretofore been proposed for controlling swaying of the trailing vehicle. Some prior devices such as disclosed in U.S. Pat. Nos. 3,400,948; 3,414,295; 3,519,287 and 3,989,269 disclose friction type brake devices for retarding swaying movement in the towing and trailing vehicles. The friction type brake devices disclosed in the above patents apply a generally constant braking action throughout the entire range of relative movement between the towing and trailing vehicle. However, the forces resisting relative angular movement of the towing and trailing vehicles should be maximum when the vehicles are travelling along a straight line and decrease when the vehicles are turning to facilitate maneuvering the vehicles around turns. Some other vehicle couplings such as shown in U.S. Pat. Nos. 2,879,079 and 3,690,699, utilize a detent arrangement for controlling swaying. While such detent arrangements maximize the forces resisting swaying when the vehicles are in-line, such detent arrangements are subject to rapid wear. My prior U.S. Pat. No. 4,002,352 discloses a vehicle coupling utilizing both a friction brake and a detent arrangement for controlling swaying.
Towing and trailing vehicles not only undergo relative pivotal movement about an upright axis during turning, but also undergo relative angular movement about axes that extend longitudinally and crosswise of the vehicles, when traversing uneven ground. It is common practice to use ball and socket type couplers between the towing and trailing vehicle, to accommodate universal angular movement therebetween. However, prior anti-sway couplers using ball and socket type hitches, for example, as disclosed in the aforementioned U.S. Pat. Nos. 3,400,948 and 3,414,295. require a relatively complex arrangement for connecting the ball and socket coupler to the anti-sway brake. Moreover, prior vehicle anti-sway couplers were generally cumbersome to couple and uncouple.